Cable operated controls are utilized in a number of control systems, as for example, braking systems and clutch control systems for automobiles. Such systems usually have a control cable which extends from an actuation member, for example a clutch or brake pedal, to a controlled member such as a brake shoe actuation mechanism or clutch. The control cable itself often extends through and is guided by a control cable conduit which serves to protect the control cable as well as to guide it around corners. The control cables in such systems usually require precise adjustment to accommodate for wear and manufacturing tolerances in the systems.
In manual shift systems of automobiles, the clutch facing plate wears during use resulting in the relatively heavy clutch spring drawing the control cable further towards the clutch and effectively shortening the cable such that play will be introduced between the clutch pedal and control cable. On the other hand in braking systems, the effective length of the control cable is lengthened as brake shoes wear down which results in undesirable play being introduced into the brake system requiring the brake pedal to be depressed excessively before a braking force is exerted.
Undesirable play can also be introduced into a control system incorporating cable conduits caused by wear between the cables and the inner walls of the conduits. In addition wear may occur between a control cable and attachments, for example sheaves over which cables extend, which further may introduce undesirable play into a control cable system.
Various mechanisms have been proposed in order to provide automatic adjustment of cable control devices to accommodate wear of the various parts as mentioned above. For example, on one manual gear shift system, a clutch control cable is connected to a clutch pedal through means of a pawl which slides over a toothed arcuate segment connected to the clutch pedal and where the pedal includes a tension spring exerting a tension on the tooth segment. Such a device however does not always effectively take up play in the system resulting from wear as in some instances, the pawl may slide over a number of teeth of the tooth segment before engaging one. Under certain driving conditions this can be dangerous when it is necessary to quickly disengage the clutch.
It is therefore an object of the invention to provide for a cable conduit mechanism which will automatically compensate for wear in a control cable system where the mechanism is easily installed in existing control cable systems and which is inexpensive to manufacture and at the same time will provide safe and positive operation.